SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c297ce61829021800eacd132c7320b6a19fa935d1a1d011bb28261f7aecb745d' 
  AND token = 'zlTbExMwPvF/82MNUBW/5pTLfUFeM1cY8PEn62VAOv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}